std::advance
From cppreference.com
Defined in header <iterator>
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template< class InputIt, class Distance > void advance( InputIt& it, Distance n ); |
(until C++17) | |
template< class InputIt, class Distance > constexpr void advance( InputIt& it, Distance n ); |
(since C++17) | |
Increments given iterator it
by n
elements.
If n
is negative, the iterator is decremented. In this case, InputIt
must meet the requirements of LegacyBidirectionalIterator, otherwise the behavior is undefined.
Contents |
[edit] Parameters
it | - | iterator to be advanced |
n | - | number of elements it should be advanced
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Type requirements | ||
-InputIt must meet the requirements of LegacyInputIterator.
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[edit] Return value
(none)
[edit] Complexity
Linear.
However, if InputIt
additionally meets the requirements of LegacyRandomAccessIterator, complexity is constant.
[edit] Notes
The behavior is undefined if the specified sequence of increments or decrements would require that a non-incrementable iterator (such as the past-the-end iterator) is incremented, or that a non-decrementable iterator (such as the front iterator or the singular iterator) is decremented.
[edit] Example
Run this code
#include <iostream> #include <iterator> #include <vector> int main() { std::vector<int> v{ 3, 1, 4 }; auto vi = v.begin(); std::advance(vi, 2); std::cout << *vi << '\n'; }
Output:
4
[edit] See also
(C++11) |
increment an iterator (function template) |
returns the distance between two iterators (function template) |